Found an old newspaper article from 1961 (appears to be the year the apartments were built).

"Tuttle" was indeed the artist - Milton Tuttle. However, based on the shading you can see in the black-and-white newspaper photo, compared with the current photo I've placed below it, it looks like the mural may have been repainted at some time.

Aha! So it was painted in the original color scheme of the mask, initially. Too bad that there is nothing left of the "South Pacific decor throughout". But at least they did a good, clean job in painting the mask, they could have just stuccoed it over.